Electrodeposition process using an aqueous emulsion containing a prepolymer and a polyalkylenimine



United States Patent Office Patented August 23, 1966 ELECTRODEPOSITIONPRGCESS USING AN AQUE- OUS EMULSION CQNTAINING A PREPOLYMER AND APOLYALKYLENIMINE Joseph F. Abere, White Bear Lake, Minn, assignor toMinnesota Mining and Manufacturing Company, St. Paul, Minn., acorporation of Delaware No Drawing. Original application Nov. 18, 1960,Ser. No. 70,115. Divided and this application .Ian. 18, 1965, Ser. No.426,406

3 Claims. (Cl. 204181) This application is a division of my prior andcopending application S.N. 70,115, filed November 18, 1960.

This invention relates to an aqueous emulsion of a resinous composition.In one aspect, the invention relates to a process for curing orcrosslinking polymers in aqueous emulsion. In another aspect, thisinvention relates to aqueous emulsions of low molecular weightprepolymers having on the average more than one active site and of acrosslinking agent.

As a result of the excellent chemical and physical properties of lowmolecular weight prepolymers, such prepolymers have been proposed foruse as coatings and impregnants on various surfaces. The flexibility andprotective and weathering properties of prepolymers in their cured formhave made them particularly attractive for use as coatings on fabrics.Heretofore, it has been suggested to apply low molecular weightprepolymers to surfaces in liquefied form or in organic solution. Theliquid prepolymers have the disadvantage of being rather viscous, havingpoor penetration properties and being incompatible with the surface;thus diflicult to apply as thin coatings. Solutions of prepolymers aredisadvantageous because of cost and the dangers resulting from thetoxicity and flammability of the organic solvents. It is much to bedesired to provide a suitable handling medium and process for curingprepolymers which can be used in connection with the treating ofsurfaces without the above disadvantages.

The object of this invention is to provide a new aqueous emulsion of lowmolecular weight prepolymers.

Another object of this invention is to provide a new fabric coatingcomposition and fabrics coated therewith.

Still another object of this invention is to provide a method forcoating leather with a composition useful, for example, asscuif-resistant compositions on shoes.

Still another object of this invention is to provide stable aqueousemulsions containing curable low molecular weight prepolymers and thecuring agent, useful for protective coating of surface, as an adhesive,as a plasticizer for other plastic compositions, etc.

Yet another object of this invention is to provide a process forproducing an emulsion of a cured or crosslinked prepolymer.

Another object of this invention is to provide a process forcrosslinking or curing of low molecular weight polymers.

Various other objects and advantages will become apparent to thoseskilled in the art from the accompanying description and disclosure.

In accordance with the invention, it has been found that low molecularWeight prepolymers, containing on the average more than one carboxylgroup per molecule, can be dispersed and cured or crosslinked in anaqueous medium in the form of an emulsion utilizing a suitableemulsifying agent. Such aqueous emulsions have a high degree ofstability while not affecting the desirable mechanical and chemicalproperties of the prepolymer con- 'tained therein.

The emulsions of this invention are prepared by mixing the prepolymersand emulsifying agent with water while vigorously agitating the mixture.Agitation may be cffected by shaking, by a paddle agitator or by apropeller. The agitation is sufficient to break up the prepolymer into aparticle size in the water of between about 5 and about 20 microns. Theprepolymer is dispersible in the water up to about 50 weight percentbased on the aqueous suspending medium. After the prepolymer has beendispersed or emulsified in the aqueous medium, a polyfunctionalethylenimine is added as the curing agent. Curing may be startedimmediately on mixing, or retarded until the emulsion is applied to thesurface, such as by cooling below 10 C. When the emulsions are coated onfabrics, paper and leather for such uses as in lightweight tarpaulins,radomes, electrical insulation, collapsible storage and shippingcontainers, protective clothing and shoes, upholstery, etc., they resultin tough, flexible coatings which are superior in many respect to thepresently used coatings.

The preferred prepolymer in accordance with this invention is a lowmolecular weight carboxyl-containing polyester obtained by thecopolymerization of a diol, a dibasic acid and a polyfunctional compoundcontaining at least three functional groups. The polyester is preparedby reacting together the above components at a temperature of about toabout 220 C. at atmospheric or elevated pressure until the reaction issubstantially complete as evidenced by the production of approximatelythe theoretical amount of water of esterification of the reaction. Thetemperature of reaction should be maintained below that temperaturewhere the particular polyester product will decompose. The reaction maybe carried out in the presence of an inert organic solvent to increasemobility of the product mixture and thereby insure completion of thereaction. Suitable organic solvents include the aromatic hydrocarbons,such as benzene, cyclic ethers, such as dioxane and tetrahydrofuran, andthe ketones, such as methyl isobutyl ketone. In one embodiment of theinvention, the diol and diacid may be prereacted together and theresulting product then reacted further with the polyfunctionalcomponent.

The amount or proportion of the specific monomers of the initialreaction mixture controls the number of carboxyl groups appended to thepolyester chain. The major proportion of the functional groups in thereaction mixture are provided by the monomers other than thepolyfunctional compound. In addition, more than half of the totalfunctional groups of the monomers in the reaction mixture must beprovided by the carboxyl-containing monomer or monomers. In order toprovide the most preferred branched polyesters (containing a pluralityof carboxyl crosslinking sites) suitable to produce elastomers, betweenabout 1 .and about 10 percent of the functional groups of the reactionmixture are provided by the polyfunctional component containing at leastthree functional groups. The polyfunctional component contains fromthree to six functon-al groups per molecule, preferably three to fourfunctional groups per molecule. A portion of the dibasic acid or diolmay be replaced with a hydroxy acid or amino acid, thus providing afourth component of the prepolymer mixture. The polyester polymer of thepresent invention should contain free carboxyl groups attached to thechain since hydroxyl groups do not generally possess the activitynecessary for moderate low temperature vulcanization or crosslinking.

Mixtures of the various reactive components may be used withoutdeparting from the scope of this invention. For example, two or morediols may be used as the diol component. Also, two or more dibasic acidsor two or more trifunctional components may be used.

In one embodiment, the polyester may be prepared by substituting ahydroxy acid for both the diol and diacid; in which case the reactionmixture is composed of a hydroxy acid and the polyfunctional compoundhaving at least three carboxyl groups.

The diol component of the polyester prepolymer is an aliphatic diol inwhich the carbon chain may or may not be interrupted with oxygen,sulfur, nitrogen, or an aromatic group, such as a phenyl group, Typicalexamples of suitable diols include neopentyl glycol (2,2-dimethyl-1,3-propanediol), diethylene glycol, polyethylene glycols (200 to 4,000molecular Weight) 2,2-bis-[4-(2-hydroxypropoxy)-phenyl]-propane,1,2-propylene glycol, 3-methyl-3-azapentandiol-l,5, 1,4-bis-(2hydroxypropoxy)benzene, 1,4-butylene glycol, 2,2-diethyll,3-propanediol,polypropylene glycols (200 to 4,000 molecular weight), polybutyleneglycols (200 to 4,000 molecular weight, 1,1,5,5,-tetrahy-droperfiuoropentane diol, and tetrahydroperfiuoropropylene-etherglycol.

The dibasic acid component of the polyester prepoiymer includes bothaliphatic and aromatic diabasic acids in which the hydrocarbon chain ofthe aliphatic acid may or may not be interrupted with oxygen or sulfur.Suitable examples of dibasic acids include succinic acid, adipic acid,glutaric acid, diglycolic acid, thiodipropionic acid, oxydipropionicacid, azelaic acid, sebacic acid, fumaric acid and maleic acid.

The polyfunctional compound providing the crosslinking sites and havingat least three functional groups include polyanhydrides, polyols andpolybasic acids. The polyols are aliphatic but may incluude an aromaticgroup, such as a phenyl group, interrupting the hydrocarbon chain. Thepoly-basic acids and polyanhydrides include both aliphatic and aromaticcompounds, Suitable examples of such polyfunctional compounds containingat least three polyfunctional groups include glycerol,trimethylolpropane, trimethylolmethane, maunitol, pentaery-thritol,trimesic acid, tricarballylic acid, benzene tetracarboxylic acid,pyromellitic dianhydride, 1,4,5,8-naphthalene tetracarboxylicdianhydride and cyclohexanetetracarboxylic acid anhydride.

Suitable hydroxy acids (including lactones) and amino acids which may beused in accordance with this invention include citric acid, l2-hydroxystearic acid, N-meth yl-fi-alanine, beta-hydroxyproponic acid,N-methyl-omegaaminoundecanoic acid, N-methyl-o-aminocaproic acid, andcaprolactone.

Typical examples of branched polyesters include the followingcombinations: glycerol, neopentyi glycol (2,2- dimethyl-l,3-propanediol)and succinic acid; trimethylolpropane, diethylene glycol, and adipicacid; trimethylolpropane, neopentyl glycol and diglycolic acid;glycerol, diethylene glycol, and adipic acid; trimethylolpropane,polyethylene glycol to 4,000 molecular weight) and thiodipropionic acid;trimethylolethane, diethylene glycol, polyethylene glycol (200 to 4,000molecular weight) and oxydipropionic acid; trimethylolpropane,2,2-bis-[4-(2-hydroxypropoxy)phenyl]-propane and azelaic acid; mannitol,diethyleue glycol and diglycolic acid; pentaerythridroxypropoxy)benzene, fumaric acid and sebacic acid; andtrimethylolpropane, 3-methyl-3 azapentandiol-l,5 and azelaic acid;trimesic acid, diethylene glycol and adipic acid; citric acid,polyethylene glycol (200 to 4,000 molecular weight) and adipic acid;citric acid, di-1,4-(2-hydroxypropoxy)benzene, fumaric acid and sebacicacid; benzene tetracarboxylic acid, propylene glycol, 1,4-butyleneglycol and adipic acid; benzene tetracarboxylic acid, polyethyleneglycol (200 to 4,000 molecular weight), and maleic acid; benzenetetracarboxylic acid, 2,2-diethy1-1,3- propanecliol, and diglycolicacid, 1,l,5,5-tetrahydroperfiuoropentanediol, adipic acid,trimethylolpropane; tetrahydroperfluoroether glycol HO CH CF CF OCF CFCH OH adipic acid, trimethylolpropane; benzene tetracarboxylic acid,l2-hydroxy stearic acid; polyacrylic acid, hydracrylic acid;pyromellitic dianhydride, polybutylene glycol (200 to 4,000molccular'weight); 1,4,5,8-naphthalene tetracarboxylic dianhydride,polypropylene glycol (200 to 4,000 molecular weight); and diethyleneglycol, adipic acid and pyromellitic. dianhydride.

Low molecular weight polymerized fatty acids which are also suitable foruse in the present invention as the carboxyl-containing prepolymer canbe characterized as polymeric fat acids of the drying and semi-dryingoils. They are derived from unsaturated monomers having at least twodouble bonds and containing acyl groups; and can therefore be designatedas polymerized polyene fatty acids. The preparation of such polymericpolyene fatty acids is described in United States Patent No. 2,482,761,No. 2,373,015 and No. 2,435,478.

The polymerized polyene fatty acids which result from the preparatoryprocesses described in the above patents can be characterized by theiraverage molecular weights. Thus, the dirneric, dibasic fatty acidpolymers prepared from C-18 acids have been described as having anaverage molecular weight of about 560 while the corresponding trimerictribasic acids have an average molecular weight of about 840. Mixturesof the dimeric and trimeric acids will have molecular weights which areintermediate these numbers, while the tetramers and mixtures containingthem will have correspondingly higher molecular weights. Illustrationsof the polymeric fatty acids which can be employed herein are, forexample, the dibasic dimerized linoleic acid of approximately 600molecular Weight which is sold under the trade name, Emery Dimer Acid3079-3; and Emery Trimer Acid 3055-8 which is a tribasic acid trimer oflinoleic acid of average molecular weight of approximately 845.

Other fatty acid polymers which are suitable for use in the presentinvention are the mixtures of polymerized fatty acids derived fromsoybean oil, peanut oil, linseed oil, dehydrated castor oil, corn oil,tung oil, cottonseed oil, sardine oil, tall oil and other oils of thedrying or semi-drying type.

Acrylic addition copolymers prepared from an alphabeta unsaturatedmonocarboxylic acid and a diene, such as a copolymer of acrylic acid andbutadiene, or methacrylic acid and isoprene, are also suitablecarboxylcontaining prepolymers for use in this invention.

of the formula /CH3 Q N CRR i.

where Q is an n valent radical, n is 2 or more (preferably 2 or 3), N islinked to an atom having a valence of 4 or 5, and R and R" are hydrogenor an alkyl group preferably having from 1 to 4 carbon atoms. Q may bean aliphatic, aromatic or alicyclic organic radical which does notcontain an active hydrogen but Which may contain atoms other thancarbon, such as oxygen, sulfur, phosphorous, nitrogen, etc. Q may alsobe an inorganic radical, such as Such phosphorus-containing alkyleniminederivatives include, for example, tris(l-aziridinyl)phosphine oxide,tris(1 aziridihyDphosphine sulfide, N,N-diethyl-N',N-diethylenethiophosphoramide, N,N diethylenbenzene,

thiophosphondiamide, N (3-oxapentamethylene)-N',N" diethylene phosphorictriamide, N,N-diethylenbenzene phosphondiamide, N,N'-diethylene ethanephosphondiamide, butyl N,N'-diethylenediamidophosphate,N,N-dioctyl-N',N"-diethylenephosphoric triamide, N,N,N"-tris(l,l-dimethylethylene)phosphoric triamide, etc.

The preferred curing agents employed are substituted polyalkylene amidesrepresented by the following illustrative formulae:

and

wherein R represents an organic radical, such as alkylene radical havingfrom 4 to 40 carbon atoms, a 1,3- phenylene radical or a 1,4-phenyleneradical, and R and R" each represent hydrogen or an alkyl radical havingfrom 1 to 8 carbon atoms.

The above curing agents included within the scope of the above formulaeare characterized by properties which permit storage without spontaneouspolymerization since they can 'be produced in substantially pure form,i.e. a product having an azirane ring content of at least 85 percent,usually at least 95 percent, of theoretical. They are controllablyreactive and are especially useful for purposes of chain extension ofcarboxyl group containing prepolymers as disclosed herein.

Among the N,N'-'bis-1,Z-alkylenamides useful as curing agents areN,N'-bis-1,2-ethylenadipamide; N,N-bis-1,2-ethylenpimelamide;N,N-bis-l,Z-ethylenisosebacamide; N,N-bis-1,2-butylenisosebacamide;N,N'-bis-1,2-ethylensebacamide; N,N' bis-1,2-ethylensuberamide;N,N-bis-1,2-propylensuberamide; N,N'-bis-1,2-butylensuberamide;N,N'-bis-1,2-ethylenazelaamide; N,N-bis-1,2-propylenazelaamide;N,N'-bis-1,2-butylenazelaamide;N,N-bis-1,Z-ethylendodecanoyldicarboxylic acid amide;N,N'-bis-l,Z-ethylentetradecanoyldicarboxylic acid amide;N,N'-bis-l,2-propylentetradecanoyldicarboxylic acid amide;N,N-bis-l,Z-ethylenhexadecanoyldicarboxylic acid amide; N,N'bis-1,2ethylenoctadecanoyldicarboxylic acid amide;N,N'-bis-1,2-propylenoctadecanoyldicarboxylic acid amide;N,N'-bis-1,2-propylendodecanoyldicarboxylic acid amide;

and N,N'-bis-1,Z-pentylensebacamide; N,N'-bis-l,Z-ethylenisophthalamide;N,N'-bis-l,Z-butylenisophthalamide; N,N'-bis-l,2-propylenisophthalamide;N,N-bis-1,2-pentylenisophthalamide; N,N'-bis-1,Z-ethylenterephthalamide;N,N'-bis-l,Z-propylenterephthalamide;N,N'-bis-l,Z-butylenterephthalamide;

etc. Mixtures of these monomers may be produced by employing mixed1,2-alkylenirnines.

l,2butylenimine, 1,2-pentylenimine, etc., is reacted with an aliphaticdicarboxylic acid chloride containing 6 to 42 carbon atoms (e.g.isosebacoyl dichloride, sebacoyl dichloride, suberoyl dichloride,azelaoyl dichloride, tetradecanoyl dichloride, dodecanoyl dichloride,hexadecanoyl dichloride and octadecanoyl dichloride), isophth-aloyldichloride or terephthaloyl dichloride; to produce the desiredsubstantially pure N,N-bis-l,2-alkylenarnide monomer, with hydrogenchloride as a by-product. The 1,2- alkylenimine is employed in a ratioof about 2 mols for each mol of acid chloride. Advantageously, an excessof l,2-alkylenimine, such as about 5 percent by weight, over and abovethis ratio may be employed, although an excess of up to about 25 percentmay be employed.

Desirably, the 1,2-alkylenimine is introduced in an aqueous solutionwhich also contains an alkali metal carbonate, such as sodium,potassium, or lithium carbonate, which acts as an acid-acceptor toneutralize the hydrogen chloride formed during the reaction of theprocess. When a higher 1,2-alkylenimine than 1,2- ethylenimine, i.e. onecontaining more than 2 carbon atoms, is employed, an alkali-metalbicarbonate, such as sodium, potassium or lithium bicarbonate, may beused as the acid-acceptor instead of a carbonate. This aqueous solutionis intimately mixed with the carboxylic acid chloride dissolved in asubstantially water-immiscible organic solvent which is chemically inertto both the reactants and the reaction products and in which theresulting N,N'-bis-l,2-alkylenamide is soluble. The N,N-bis-1,2-alkylenamide monomer reaction product is then recovered in arelatively pure, stable state in high yield from the organic solvent, inwhich it collects as the reaction proceeds, by evaporating the solvent.By this process of producing the monomers any possibility of attack onand decomposition of the alkylenamide product by hydrogen chlorideformed during the course of the reaction is effectively minimized.

In producing N,N-bis-l,2-alkylenamides of 1,2-ethylenimine, pH controlof the reaction mixture is more critical than where alkyleniminescontaining more than 2 carbon atoms are employed. Thus, in such cases itis important to employ an alkali-metal carbonate as the acidacceptor inan amount sufficient to neutralize all of the hydrochloric acid formedduring the reaction of the process and yet maintain the pH of thereaction mixture at about 8.5 or above. With 1,2-alkyleniminescontaining more than 2 carbon atoms, on the other hand, an alkalimetalbicarbonate may be employed instead of an alkalimetal carbonate as theacid-acceptor, so long as sufficient bicarbonate is present toneutralize all of the hydrochloric acid formed. This phenomenon isbelieved to be the consequence of the greater reactivity of ethyleniminewhen compared to those alkylenimines containing more than 2 carbonatoms. The prevention of decomposition of the bis-alkylenamide monomerby the hydrogen chloride formed during the process which this processprovides is critical to the production of stable monomer product inuseful amounts.

Illustrative of the bis-canbamates which are useful as curing agents inthe present invention are:

N,N'-bis-1,2-ethylene (1,4-butanediol) carbamate; N,N-bis-1,2-propylene(1,4-butane-diol) carbamate; N,N-bis-l,2-butylene (1,4-butanediol)carbamate; N,N'-bis-1,2-ethylene (diethylene glycol) carbamate;N,N'-bis-1,2-butylene (diethylene glycol) carbamate;N,N'-bis-1,2-ethylene (triethylene glycol) carbamate; N,N'-bis-1,2-propylene (triethylene glycol) carbamate; N,N-bis-l,2-butylene(triethylene glycol) carbamate; N,N-bis-1,2-ethylene (polyethyleneglycol-200) carbamate; N,N'-bis-1,2-ethylene (polyethylene glycol-400)carbamate; N,N-bis-l,2-ethylene (polyethylene glycol-1000) carbamate;

N,N'-bis-1,2-propylene (polyethylene glycol-1000) carbamate;

N,N-bis-1,2-ethylene (polyethylene glycol-4000) carba mate;

N,N'-bis-1,2-ethylene (polypropylene glycol-1025) carba- 5 mate;

N,N-bis-1,2-ethylene (polybutylene glycol-500) carbamate;

N,N- bis-1,2-ethylene l, l -isopropylidene-bis- (p-cyclohexanol)]carbamate;

N,N'-bis-1,2-ethylene [1, l'-isopropylidene-bis-(p-phenylene oxy)di-2-prop anol] carbamate;

N,N'-bis-l,2-ethylene phenylenoxy diocetamide;

N,N"-bis-1,2-ethylene phenylenoxy carbamate;

N,N'-bis-1,2-ethylene-4,4'-bisphenyl carbamate; l

N,N'-bisl ,2-ethylene( l, l-isopropylidene-bisphenylene) carbamate;

N,N-bis-ethyleneresorcinol carbamate, etc.

The preferred aromatic carbamates are represented by the above formulawherein R is 1,3-phenylene, 1,4-phenylene,1,1'-isopropylidenebis-phenylene, or l,l'-isopropylidenebis-(p-phenyleneoxy)di-2-propanol. The referred aliphatic carbamates are represented bythe above formula wherein R is a branched or straight chain alkyleneradical having from about 4 to about 40 preferably from about 4 to about20, carbon atoms.

Generally, their preparation involves the reaction of a 1,2-alkyleniminein a water phase with a solution of a chlorocarbonate of a difunctionalalcohol in a water-immiscible organic solvent, in the presence of anacid-acceptor, at a temperature between about 5 C. and 30 C.

In the preparation of the compositions of the invention, thepolycarboxyl group containing prepolymers are employed in emulsifiedform in an aqueous medium. To the emulsified polycarboxyl prepolymer isadded the polyalkylenimine curing agent which is to be employed. Whilean amount of the curing agent which is equivalent stoichiometrically tothe number of carboxyl groups present may be employed, and somedesirable curing elfects can be obtained with even smaller amounts, fullcures are effected when amounts greater than stoichiometric amounts areemployed, ranging upwards from to 100 percent greater; and it isordinarily preferred that about to percent excesses of the theoreticalstoichiometric equivalent of the curing agent be used in order tocompensate for any inerts in the curing agent, its adsorption on andreactivity with fillers, etc. Curing is effected at a temperaturebetween about room temperature (22 C.) and about 150 C. In someinstances, the cure is initiated as soon as the two components are mixedin the emulsion; therefore, the emulsion may have to be applied to thesurface to be coated soon after adding the curing agent. The rate ofcure is dependent upon the particular curing agent employed, theprepolymer, the temperature, the viscosity of the mixture and the amountof the curing agent. By maintaining the dispersion at low temperatures,for example, about 015 C., the curing is retarded and increased pot lifeis obtained. Curing may also be retarded by the use of a basic emulsion,or the use of a curing agent which requires elevated temperatures tostart the curing or crosslinikng reaction. The curing agent may besoluble or insoluble in the aqueous medium.

If desired, fillers can be added to the dispersion as well as dyes orother substances which may be considered as adjuvants and the like, forexample, accelerators, antioxidants and catalysts. The finer fillers aregood reinforcing agents for these systems, neutral fillers such ascalcium carbonate, iron oxide and titanium dioxide being preferred.Acidic fillers such as certain carbon blacks and silicas can also beused if proper adjustments are made for pH (e.g. addition of increasedamounts of curing agent).

The prepolymer and curing agent composition of this invention can beconveniently handled and applied to surfaces from these aqueousemulsions. it has been found that the water-insoluble prepolymers may besuspended in aqueous medium in an amount between about 5 and about 50weight percent based on water. The crosslinking agents, such as thepolyalkylenamide hereinbefore described, may be included in thedispersion together with filler-s, pigments, and dispersing andemulsifying agents which are present in an amount of about 0.1 to 20weight percent based on water.

Among the emulsifying agents that are useful for dispersing 'theprepolymers in the aqueous 'vehicle, the following are examples:

Morpholine salts of fatty acids of 12-18 carbon atoms such as monpholineoleate and stearate; acetates of nprimary amines having 12-18 carbonatoms in amine chain such as n-dodecyl amine acetate, n-octadecyl amineacetate, n-octadecenyl amine acetate and n-octadecadienyl amine acetate;monesters of polyethylen glycols and fatty acids of 12-18 carbon atomssuch as heX-aethylene glycol monooleate; alkylaited aryl polyet-heralcohols; alkali metal soaps of fatty acids of 1218 carbon atoms; soapsof alkalis such as valkanolantr-ines, borax, morpholine, ammonia,alkali-metals and the like with acids such as oleic acid, red oil, mixedamino (fatty acids, and the like; -di-n-' octyl sodium sulfosuccinate;oleic acid condensate of polyethylene oxide; sodium salt of secondaryalkyl sulfate; aryl alkyl polyet-her alcohols; and aryl polyetheralcohols.

Suitable emulsifying agents include potassium oleate, sodium stearate,sodium lauryl sulfate, sodium salt of long chain alkyl sulfouatesderived from kerosene, ammonium salt of perfluorooctanoic acid, lithiumsalt of penflu0r0 octane sulfonic acid, potassium salt of-N-ethyl-N-penfluorooctanesulfonyl 'glycer-ine, and ethylene oxidederivatives of alkylated phenols.

These dispersing or emulsifying agents are usually in cluded in anamount between about 0.1 and about 15 weight percent based upon thewater content of the dispersion. The dispersion is prepared by adding:the emul si-fying agent to water and then adding the prepolymer to thewater solution. The curing agent is usually added to the emulsion justprior to use, but this is not always necessary. In some instances, anorganic solvent, such as toluene, is used as a means for dissolving thecuring agent r or the prepolymer and aiding in the dispersion of thesecomponents in the aqueous medium. Dispersions made in accordance withthe above may be utilized for protectively coating sunfaces or formaking up compositions which include other materials, such asplasticizers for vinyl polymer, in paper making, or for the saturationand treatment of fabrics and paper, or as an adhesive or primer to bused as an intermediate layer.

As previously stated, the aqueous emulsion of this invention can beapplied to various surfaces, such as synthetic fabrics, paper, andmetal, but one of the most unique and best applications of the aqueousemulsion is to leather surfaces either as an impregnant or as a coating.Leather which may be treated with the aqueous emulsion of this inventioncontaining a curing agent and then cured includes rawhide, cowhide,pigskin, does-kin, kid and alligator hide. Such finished or coatedleather may be used for shoes, shoe soles, pocketbooks, belts,industrial gaskets and seals, harnesses, saddles, briefcases, luggage,table tops, chairs, gloves, coats and jackets. The leathers coated withthe dispersion of the prepolymer and cured are tough andscuff-resistant. Such leathers are also Waterproof. The flex propertiesand general appearance of the leather are not affected by the curedprepolymer coating. The prepolymer emulsion may be utilized as a basecoat, a primer coat or adhesive coat, or as a top coat for leather whencured in situ. When used as a top coat, the dry tanned leather ismechanically worked to render it supple. Next, the pigment coats areapplied usually from water dispersions in a natural or synthetic resin.

The pigment is usually included in the resin and then dispersed in theaqueous medium. Natural resins include shellac or albumin but may bereplaced with synthetic acrylic or urethane resins. The top coat is thenapplied also from a water dispersion. This top coat in accordance withthis invention is an aqueous emulsion of the prepolymer and curing agentwith or without dyes, pigments or fillers, such as silica, titaniumdioxide, talc, carbon black, aniline dyes and powdered metals, such ascopper or silver. The coats may be applied byspraying, swa'txbing orbrushing.

The present emulsion is particularly useful as an adhesive coating forapplying highly fiuorinated polymer films to surfaces, such as metal,glass and plastic sunfaces. Examples of fluorinated polymers areelastomeric copolymers of vinyliden fluoride and trifiuorochloroethyleneor perfluoropropene.

The following typical examples relate to the preparation of the startingmaterials and the emulsion as well as the use of the resultingemulsions. The proportions shown in parts are parts by weight.

Example I This example is a bulk preparation of a saturated polyester ofadipic acid, diethylene glycol and trimethylolpropane. About -84 grams(4.0 mols) of adipic acid, 388 grams (3.7 mols) of diethylene glycol,12.44 grams (0.09 mols) of trimethylolpropane and 2 grams of a triphenylphosphite catalyst Were charged to a stirred flask. The

reaction mixture contained 5 percent excess of canboxyl Inherentviscosity in acetone 0.13

Number average degre of polymerization (X 50 Molecular weight (M(average) 5000 Free carboxyl groups per molecule (average) 2.6 Acidconcentration (mini-equivalents per gram) 0.50

Example II A water emulsion of a carboxylic acid-terminated polyester(adipic acid diethylene glycol polyester of Example I) was prepared. Tothis emulsion could be added a curing agent and dispersed along with thepolyester emulsion. Such dispersions find wide utility in many areas,such as coatings for wood and metal, treatments for cloth, paper, asbeater additives and in addition almost any other application wherepresently used polymeric emulsions and dispersions and latices areemployed. In this example, the emulsion formation is shown below:

Parts Water 100 Polyester 20 Toluene 20 Soap (sodium lauryl sulfate) 3N,N'-bis-1,2-ethylenisosebacamide 4 to 8 This formulation was used byaddition to paper pulp with a beater. The transparency of the resultingpaper sheet was very good and the tensile strength was increased whilethe tear strength remained the same on the sheet. In addition to thedevelopment of improved paper properties, the resulting sheet wastransparentized.

Example III A dispersion prepared from the same formula as employed inpaper making of Example II was also found useful in the making of rubbergoods from latex, by

10 electrodeposition. This technique may be employed to manufacture sucharticles as rubber gloves by plating out the elastomer on a ceramicglove form coated with a conductive layer. In this experiment a 6-voltD.C. supply was connected to a l2-oh-m rheostat switch, and two copperelectrodes in series. As the current flowed from one electrode toanother through the emulsion, the dispersed particles of polyesterelastomer plated out and discharged on the anode. It was found that aselectrodeposition proceeded, current blocking occurred (as filmthickness increased on the anode) while the cathode (and rod) rernaineduncoated. The coated anode was placed in an oven for 20 minutes at 120C., and cured to a strong elastomer showing that a continuousimpermeable film of electrodeposited elastomer had been formed from thedispersion.

Example IV The preparation of scuff-resistant finishes for leather frompolyester elastomers can also be achieved from latex or waterdispersion. In a typical experiment, a master-batch was prepared on apaint mill consisting of parts of the polyester of Example I, 15 partssilica, and 2 parts Agerite White antioxidant. This master-batch wasdispersed in :a small amount of water containing an emulsifier, such assodium lauryl sulfate, just enough to allow the coating to be spreadfreely over the leather surface. The dispersion formulation was 5 partspolyester master-batch, 1 part bis-eithylenisosebacamide, 1 parttoluene, and 20 parts water. Coatings of this formulation were spread byhand with a brush to work it evenly over the leather. The spread coatingwas cured by infrared lamps. A firm tack-free abrasion-resistant clearcoating results. Onto this base coat could be deposited the variousconventional finishing coats, if desired.

Example V The following emulsion formulation was used to make updifferent emulsions which were then used to coat both full grain leatherand black buff leather.

Standard formulation: Parts Water 100 Prepolymer 10 Curing agent l to 10Emulsifier 1 Acid-acceptor 1 Antioxidant 0.2

Prepolymers used in the above formulation to make the differentemulsions were neopentyl glycol sebacate (tri-methylolpropane cured)polyester, neopentyl glycol isosebacate (trimethylolpropane cured)polyester, Emery Dimer acid, addition copolymer of acrylic acid andbutadiene, 3,3'-oxy-bis-tetrafluoropropanol adipate (trimethylolpropanecured) polyester, a copolymer of dimethyldiethoxysilane andbeta-carbethoxypropyl methyl diethoxy silane, and diethylene glycoladipate (trimethylolpropane cured) polyester.

Curing agents used in the above formulation to make the differentemulsions include N,N'-bis-1,2-ethylenisosebacamide,N,N'-bis-1,2-butylenisosebacamide, N,N'-bis-l,2-propylenisosebacarnide,N,N-bis-l,Z-ethylenisophthalamide, N,N-bis-1,2-propyenisophthalamide,Bis-ethylencarbamate of bis-phenol A, and Tris-aziridinyl phosphineoxide.

Emulsifiers used in the above formulation to make up different emulsionsinclude NaOSO CH CH N CH COOC H (Igepon T-77) C F SO OK, sodiumstearate, sodium lauryl sulfate, n-alkyl trimethyl ammonium chloride,stearyl dimethy-l benzyl ammonium chloride, chloride,

alkyl polyoXyet-hylene amine, lauric alkylolamine condensate and NaOSOCH CH CH(C H )CH CH CH(OH)CH CH CH(C H )CH OH (Tergitol-7 A suitableacid-acceptor is morpholine and suitable antioxidant is sym.di-beta-naphthyl-para-phenylenediamine (Agerite White).

All of the above components are useful in combination to make up theemulsion formulation. For example, a useful emulsion has been found tocomprise in parts by Weight in accordance with the basic formulation,Water, neopentyl glycol sebacate, N,N'-bis-1,2-ethylenisosebacamide, C FSO OK, morpholine and di-beta-naphthyl-paraphenylenediamine. If desired,about 2 parts of an aromatic hydrocarbon, such as toluene, may be addedto the emulsion as an aid to emulsifying the components thereof. Theabove emulsions are stable up to three weeks and longer. Strong plasticor elastomeric films in cured form have been cast from such emulsions.These emulsions when applied to leather show good dryingcharacteristics, good oil and water repellency, and materially improvethe scufl resistance of the leather finish. The spreading quality of theaqueous dispersions are good and in most instances give a smooth,transparent, glossy appearance.

Plastisols can be made from the emulsions of this invention by includingin the emulsion, in addition to the above components, a vinyl plastic orelastomers, such as polymers and copolymers of vinyl chloride, vinylfluoride, vinyl acetate, styrene, bu-tadiene, trifiuorochloroethylene,tetrafiuoroethylene. The vinyl plastic or elastomer is included in theemulsion in an amount between about 10 and about 50 weight percent basedon water. In such plastisols, the vinyl resin is usually the majorconstituent compared to other dispersed or dissolved ingredients. Suchplastisols when in emulsified form are applied to the surface to becoated and dried. The prepolymer acts as a plasticizer for the vinylresin and is cured in situ thus minimizing or eliminating bleeding ofthe plasticizer from the coating or fihn.

When curing or polymerization is effected in the aqueous phase, themaximum temperature employed is about 100 C.

The carba-mates as curing agents are usually soluble in the aqueousphase while the bisamide-type curing agent is usually insoluble. Thesiloxane prepolymers are particularly useful as coatings or impregnatesfor leather as they give high gloss to the finish. The trisamide-typecuring agents are particularly useful in curing prepolymers having onlytwo carboxyl groups since this results in a space polymer rather thanmerely a chain-extended polymer. In addition to phosphorus-containingtrisamides, as useful in this invention areN,N,N"-tris-ethylenetrimesamide, N,N',N" tris 2methylethylenetrimesamide and N,N,N"-tris-2-propylethylenetrimesamide.

Various alterations and modifications of the compositions and their usesmay become obvious to those skilled in the art Without departing fromthe scope of this invention.

Having described my invention, I claim:

1. An electrodeposition process which comprises passing an electricalcurrent between an anode and a cathode in an aqueous emulsion containinga carboxyl containing prepolymer and a polyalkylenimine and recoveringsaid anode having a coating comprising said prepolymer andpolyalkylenimine.

2. An electrodeposition process which comprises passing an electricalcurrent between an anode and a cathode in an aqueous emulsion containinga prepolymer having an average of more than one carboxyl group permolecule and a polyalkylenimine, recovering the anode coated withprepolymer and polyalkylenimine, and thereafter curing the coating onthe anode at an elevated temperature to form a continuous impermeablefilm.

3. An electrodeposition process which comprises passing an electricalcurrent between an anode and a cathode in an aqueous emulsion containinga polyester having an average of more than two carboxyl groups permolecule and a bis-alkylenamide, recovering the anode coated withpolyester and polyalkyleni-mine, and thereafter curing the coating onthe anode at an elevated temperature to form a continuous impermeableelastomeric film.

References Cited by the Examiner UNITED STATES PATENTS 1,589,330 6/1926Sheppard et a1. 204-182 1,804,920 5/1931 Edwards 204182 2,530,36611/1950 Gray 204181 2,601,597 6/1952 Daniel et al l62164 2,933,4164/1960 Haakh et :al 117-403 JOHN H. MACK, Primary Examiner.

E. ZAGARELLA, Assistant Examiner.

1. AN ELECTRODEPOSTION PROCESS WHICH COMPRISES PASSING AN ELECTRICALCURRENT BETWEEN AN ANODE AND A CATHODE IN AN AQUEOUS EMULSION CONTAININGA CARBOXYL CONTAINING PEPOLYMER AND A POLYALKYLENIMINE AND RECOVERINGSAID ANODE HAVING A COATING COMPRISING SAID PREPOLYMER ANDPOLYALKYLENIMINE.